akka.actor.dungeon.ChildrenContainer.scala Maven / Gradle / Ivy
/*
* Copyright (C) 2009-2019 Lightbend Inc.
*/
package akka.actor.dungeon
import scala.collection.immutable
import akka.actor.{ ActorRef, ChildNameReserved, ChildRestartStats, ChildStats, InvalidActorNameException }
import akka.util.Collections.{ EmptyImmutableSeq, PartialImmutableValuesIterable }
/**
* INTERNAL API
*/
private[akka] trait ChildrenContainer {
def add(name: String, stats: ChildRestartStats): ChildrenContainer
def remove(child: ActorRef): ChildrenContainer
def getByName(name: String): Option[ChildStats]
def getByRef(actor: ActorRef): Option[ChildRestartStats]
def children: immutable.Iterable[ActorRef]
def stats: immutable.Iterable[ChildRestartStats]
def shallDie(actor: ActorRef): ChildrenContainer
// reserve that name or throw an exception
def reserve(name: String): ChildrenContainer
// cancel a reservation
def unreserve(name: String): ChildrenContainer
def isTerminating: Boolean = false
def isNormal: Boolean = true
}
/**
* INTERNAL API
*
* This object holds the classes performing the logic of managing the children
* of an actor, hence they are intimately tied to ActorCell.
*/
private[akka] object ChildrenContainer {
sealed trait SuspendReason
case object UserRequest extends SuspendReason
// careful with those system messages, all handling to be taking place in ActorCell.scala!
final case class Recreation(cause: Throwable) extends SuspendReason with WaitingForChildren
final case class Creation() extends SuspendReason with WaitingForChildren
case object Termination extends SuspendReason
class ChildRestartsIterable(stats: immutable.Map[_, ChildStats])
extends PartialImmutableValuesIterable[ChildStats, ChildRestartStats] {
override final def apply(c: ChildStats) = c.asInstanceOf[ChildRestartStats]
override final def isDefinedAt(c: ChildStats) = c.isInstanceOf[ChildRestartStats]
override final def valuesIterator = stats.valuesIterator
}
class ChildrenIterable(stats: immutable.Map[_, ChildStats])
extends PartialImmutableValuesIterable[ChildStats, ActorRef] {
override final def apply(c: ChildStats) = c.asInstanceOf[ChildRestartStats].child
override final def isDefinedAt(c: ChildStats) = c.isInstanceOf[ChildRestartStats]
override final def valuesIterator = stats.valuesIterator
}
trait WaitingForChildren
trait EmptyChildrenContainer extends ChildrenContainer {
val emptyStats = immutable.TreeMap.empty[String, ChildStats]
override def add(name: String, stats: ChildRestartStats): ChildrenContainer =
new NormalChildrenContainer(emptyStats.updated(name, stats))
override def remove(child: ActorRef): ChildrenContainer = this
override def getByName(name: String): Option[ChildRestartStats] = None
override def getByRef(actor: ActorRef): Option[ChildRestartStats] = None
override def children: immutable.Iterable[ActorRef] = EmptyImmutableSeq
override def stats: immutable.Iterable[ChildRestartStats] = EmptyImmutableSeq
override def shallDie(actor: ActorRef): ChildrenContainer = this
override def reserve(name: String): ChildrenContainer =
new NormalChildrenContainer(emptyStats.updated(name, ChildNameReserved))
override def unreserve(name: String): ChildrenContainer = this
}
/**
* This is the empty container, shared among all leaf actors.
*/
object EmptyChildrenContainer extends EmptyChildrenContainer {
override def toString = "no children"
}
/**
* This is the empty container which is installed after the last child has
* terminated while stopping; it is necessary to distinguish from the normal
* empty state while calling handleChildTerminated() for the last time.
*/
object TerminatedChildrenContainer extends EmptyChildrenContainer {
override def add(name: String, stats: ChildRestartStats): ChildrenContainer = this
override def reserve(name: String): ChildrenContainer =
throw new IllegalStateException("cannot reserve actor name '" + name + "': already terminated")
override def isTerminating: Boolean = true
override def isNormal: Boolean = false
override def toString = "terminated"
}
/**
* Normal children container: we do have at least one child, but none of our
* children are currently terminating (which is the time period between
* calling context.stop(child) and processing the ChildTerminated() system
* message).
*/
class NormalChildrenContainer(val c: immutable.TreeMap[String, ChildStats]) extends ChildrenContainer {
override def add(name: String, stats: ChildRestartStats): ChildrenContainer =
new NormalChildrenContainer(c.updated(name, stats))
override def remove(child: ActorRef): ChildrenContainer = NormalChildrenContainer(c - child.path.name)
override def getByName(name: String): Option[ChildStats] = c.get(name)
override def getByRef(actor: ActorRef): Option[ChildRestartStats] = c.get(actor.path.name) match {
case c @ Some(crs: ChildRestartStats) if crs.child == actor => c.asInstanceOf[Option[ChildRestartStats]]
case _ => None
}
override def children: immutable.Iterable[ActorRef] =
if (c.isEmpty) EmptyImmutableSeq else new ChildrenIterable(c)
override def stats: immutable.Iterable[ChildRestartStats] =
if (c.isEmpty) EmptyImmutableSeq else new ChildRestartsIterable(c)
override def shallDie(actor: ActorRef): ChildrenContainer = TerminatingChildrenContainer(c, Set(actor), UserRequest)
override def reserve(name: String): ChildrenContainer =
if (c contains name)
throw InvalidActorNameException(s"actor name [$name] is not unique!")
else new NormalChildrenContainer(c.updated(name, ChildNameReserved))
override def unreserve(name: String): ChildrenContainer = c.get(name) match {
case Some(ChildNameReserved) => NormalChildrenContainer(c - name)
case _ => this
}
override def toString =
if (c.size > 20) c.size.toString + " children"
else c.mkString("children:\n ", "\n ", "")
}
object NormalChildrenContainer {
def apply(c: immutable.TreeMap[String, ChildStats]): ChildrenContainer =
if (c.isEmpty) EmptyChildrenContainer
else new NormalChildrenContainer(c)
}
/**
* Waiting state: there are outstanding termination requests (i.e. context.stop(child)
* was called but the corresponding ChildTerminated() system message has not yet been
* processed). There could be no specific reason (UserRequested), we could be Restarting
* or Terminating.
*
* Removing the last child which was supposed to be terminating will return a different
* type of container, depending on whether or not children are left and whether or not
* the reason was “Terminating”.
*/
final case class TerminatingChildrenContainer(
c: immutable.TreeMap[String, ChildStats],
toDie: Set[ActorRef],
reason: SuspendReason)
extends ChildrenContainer {
override def add(name: String, stats: ChildRestartStats): ChildrenContainer = copy(c.updated(name, stats))
override def remove(child: ActorRef): ChildrenContainer = {
val t = toDie - child
if (t.isEmpty) reason match {
case Termination => TerminatedChildrenContainer
case _ => NormalChildrenContainer(c - child.path.name)
} else copy(c - child.path.name, t)
}
override def getByName(name: String): Option[ChildStats] = c.get(name)
override def getByRef(actor: ActorRef): Option[ChildRestartStats] = c.get(actor.path.name) match {
case c @ Some(crs: ChildRestartStats) if crs.child == actor => c.asInstanceOf[Option[ChildRestartStats]]
case _ => None
}
override def children: immutable.Iterable[ActorRef] =
if (c.isEmpty) EmptyImmutableSeq else new ChildrenIterable(c)
override def stats: immutable.Iterable[ChildRestartStats] =
if (c.isEmpty) EmptyImmutableSeq else new ChildRestartsIterable(c)
override def shallDie(actor: ActorRef): ChildrenContainer = copy(toDie = toDie + actor)
override def reserve(name: String): ChildrenContainer = reason match {
case Termination => throw new IllegalStateException("cannot reserve actor name '" + name + "': terminating")
case _ =>
if (c contains name)
throw InvalidActorNameException(s"actor name [$name] is not unique!")
else copy(c = c.updated(name, ChildNameReserved))
}
override def unreserve(name: String): ChildrenContainer = c.get(name) match {
case Some(ChildNameReserved) => copy(c = c - name)
case _ => this
}
override def isTerminating: Boolean = reason == Termination
override def isNormal: Boolean = reason == UserRequest
override def toString =
if (c.size > 20) c.size.toString + " children"
else c.mkString("children (" + toDie.size + " terminating):\n ", "\n ", "\n") + toDie
}
}
© 2015 - 2024 Weber Informatics LLC | Privacy Policy